This invention pertains to the field of control systems for scale model railroad layouts, and specifically to improvements in control of whistle sound effect generation capabilities.
The era of prototype steam-powered locomotives carrying significant railroad tonnages has passed, but nostalgic model railroaders enjoy the sounds of xe2x80x9clive steamxe2x80x9d on model railroad layouts. In addition to steam xe2x80x9cchuffxe2x80x9d sounds of moving steam locomotives, bell and steam whistle effects are particularly favored by modelers.
A steam powered locomotive whistle is very distinctive, and many new innovations in model railroad sound systems strive to provide realistic and controllable whistles on scale model railroad layouts. Examples of this would be modern DCC controlled sound decoders from Soundtraxx Inc. and ESU Electronics. Novosel et al, in U.S. Pat. No. 5,855,004 show us the benefit of digitally generated sounds in locomotive decoders, and follows prior work done by pioneers such as Soundtraxx and others.
On non-digital or conventional analog DC controlled model railroads the Pacific Fast Mail or PFM sound system has been very popular and creates very realistic sound images that are synchronized to the motion of the model locomotives, particularly narrow-gauge models. A favorite PFM sound effect is a xe2x80x9cplayablexe2x80x9d or variable pitch steam whistle, which recreates the action of a prototype engineer varying the whistle steam valve to modulate the steam whistle pitch, harmonics and intensity. This provides a lot of realistic xe2x80x9ccharacterxe2x80x9d to the operation of a model locomotive. The PFM system effects the playable whistle with a hand operable pivoting whistle pitch control lever on the control unit. In the rest position this whistle pitch control lever ensures that no whistle sound is generated. As the lever is actuated and its angle is changed the whistle sound effect is generated and is modified in pitch proportionally to the lever angle. Thus moving the lever up and down allows the generation of a controllable, continuously variable and playable whistle.
In the PFM design the sounds created in this manner are conducted from the control unit via the layout rails to a speaker mounted in the locomotive, and optionally to speakers mounted around the layout. This arrangement permits a single high quality sound system for one train on the rails connected to a single control unit. Several other sound control units exist, for example units from Model Rectifier Corporation and Chicago International that employ slider controls to allow a modeler to create a playable whistle on a conventional DC model railroad layout.
To date the only variable pitch whistle effects that have been introduced into digitally controlled model railroads are within the Marklin GmbH 1-Guage sound units on layouts controlled by their digital control system. In this system an accessory control key associated with whistle control is depressed on the control unit, or throttle, that activates the whistle in the digital sound generator in the model locomotive, and is also used to indirectly control a variable whistle pitch. After the locomotive whistle is activated by the whistle key depression, the whistle pitch begins to change in the digital sound generator in a manner controlled in proportion to the time the key is depressed. This provides a controllable whistle pitch with the standard Marklin control system components, but lacks the impression of continuously variable pitch that a lever or slider control creates. This Marklin control method, since it is a digital control system, has the desirable advantage that it permits the realistic operation of a multiplicity of whistle equipped digital locomotives in the same area of layout tracks. In this manner the prior art provides playable whistle effects, but with limitations in all the implementations.
This invention overcomes the limitations of prior user interfaces on model railroad digital control systems and provides for a more realistic feeling variable whistle control feature. This invention allows existing accessory control key array designs to be upgraded to add proportional Z-axis or force measurement localized or explicitly attached to any existing individual keys. This allows the improved proportional control of any feature controlled by such upgraded accessory control keys. This is of great benefit to expanding the control capability of user interfaces for digitally controlled model railroads.
Computer input devices have been developed to a fine, art with examples such as Parsons in U.S. Pat. No. 5,287,089 and Ono et al. U.S. Pat. No. 5,555,004. All this work is aimed at providing force sensitive computer input pointing devices that are fully integrated as a device that is manufactured as a single assembly. These mechanisms are not designed as an adjunct or upgrade to add capabilities to an existing conventional key array structure. The implied or derived force measurement is used to provide X and Y position or a selection click or double-click as a user input, and is not localized to attaching extra sense capability to any single key in a key array.
For model layouts using digital control systems the fundamental problem for allowing realistic playable whistle effect is that the user input or control devices such as throttles have all been designed for binary state or on-off actuation of accessory function devices on the layout. Prior art digital control designs have made no provision for throttles to have proportional actuation of accessory function controls, excepting that rotary knobs or slide controls are allocated for locomotive speed control. It is possible to mount a control lever or slider on a throttle for proportional actuation accessory control but these require extra space and add extra cost, as they are additional to the standard controls that have been heretofore provided.
Prior art railroad digital control systems associate sound controls with a small array of general-purpose on-off accessory function keys or switches on the input device or throttle. This has been sufficient to date to allow a repertoire of sounds to be controlled. For example accessory function keys are individually allocated to simply toggle on or off a bell, coupler clank noise, steam dynamo, steam cylinder blow-down and other discrete effects. This array of accessory function keys for controlling effects needs to be redesigned to permit proportional control input actuation capability.
A proportional control actuation key capability may be awkward to implement, and needs to fall within the control format of the overall accessory key array, so that for example, a steam whistle effect function key on one locomotive may be used for some other feature on a different type of locomotive that has no whistle but needs available function controls for other features. It is undesirable to allocate and specially build a non-array key that is only associated with a single type of capability.
The solution to this problem that this invention employs is to add an extra dimension of controllability to the accessory function switch array by allowing a Z-axis or force normal to a function key to be used as an analog or continuous input associated with that key. This means that the pressure exerted by a fingertip on a key may be used to both start an accessory function active and also then be used to vary the same accessory function by applied pressure changes. This provides a variable control input capability while allowing the key to be a standard unit within a standard function key array.
There are a number of everyday items that permit proportional control by a human hand. For example; a computer game joystick, a force sensitive eraser-head pointing device added between keys in a computer keyboard and a force sensitive touch pad computer pointing device. All these common examples differ from this invention in that the proportional force sensing capabilities are specialized devices, and are not used to upgrade a force insensitive general-purpose control switch array to a higher level of control capability.
This invention specifically is used to add Z-axis sensing capability to a key array design without Z-axis sense capability. This may be applied selectively to either a single key or any number of keys in the array. This feature is of value since it permits the selective design upgrade of a standard or inexpensive key array, or array of same types of key devices, to have a new and useful proportional control capability. The addition of proportional control capability is accomplished within the footprint of the key array so outwardly to the human interface there is no need for extra tooling or package design changes to the exterior of the enclosure supporting the keys.